The Jeffersons is the longest running African American sitcom to date, followed by Family Matters(9 seasons) and The Cosby Show(8 Seasons).
The Jeffersons outlasted its parent series All in the Family (with 9 seasons) by 2 seasons. The Jeffersons also stayed on 6 years after All in the Family ended its run.
Factual error: when Bentley is explaining to Jessica about helium, he mentions that oxygen is number 6 on the periodic table of elements. Oxygen is actually number 8, whereas number 6 is carbon.